Note that the copyright status of stamps, especially recent ones, is often obscure; US stamps before 1978 are in the public domain, as are all Soviet and Russian stamps, while Sweden claims copyright on all designs ever issued.

To get the most professional appearance, use a flatbed scanner rather than a camera, use a black background, align the stamps carefully, and leave a thin black margin outside the perforations, so that the entire physical stamp is visible. Scan at the highest resolution possible; 1200 or even 2400 DPI is good.